Signals transmitted between components of a radio communication network such as a base station and a mobile terminal may include different kinds of distortion components which can disturb receiver performance.
Wireless communication networks 100 may use channel state information (CSI) and channel quality indicators (CQI) 102 as shown in FIG. 1 to represent the channel quality or the corresponding reception performance. An estimate of channel state information 102 between the transmitted signal at a transmitter 110, e.g. a base station and the received signal at a receiver 120, e.g. a mobile terminal of a communication link may be based on limited observations at the receiver 120. In particular, the CSI may be sensitive to effects not visible in the reference symbols embedded into the downlink stream, e.g. cell specific reference symbols (CRS) or channel state information reference symbols (CSI-RS). Examples for such scenarios are non-colliding interference scenarios, i.e. interferer CRS don't collide with those from serving cell and interferer is not fully loaded and colliding interference with different power in carriers used for reference symbols as compared to data carriers.
A small difference between the coding rate for CSI at the receiver 120 and the coding rate for the transmitted signal at the transmitter 110 is inherent due to the granularity of the modulation and coding scheme (MCS) 104. Also very frequently differences in coding rates between CQI and scheduled MCS are due to “mis-configuration” issues, e.g. wrong CQI to MCS mapping 112. These small differences in coding rate may lead to a significant increase of the block error rate (BLER) 106, e.g. above 10 percent of a target BLER and subsequently an increased error rate of acknowledged/non-acknowledged transport blocks 108.
Methods and devices employed in wireless communication networks constantly have to be improved. In particular, it may be desirable to improve the reporting of channel state information of the mobile receiver in situations as described above.